A conventional soap feeding device comprises a housing, a drive means, an infrared sensor, and a feeding means. A reservoir for storing soap is provided in the housing. A barrel is attached to the outlet in the bottom of the soap reservoir. A slidable valve provided is in the barrel. Valve is a plate member having a plurality of through holes, an annular membrane adhered to the wall of the barrel, a spindle passed through the valve, a spring put on upper part of the spindle, a poppet sleeved on the lower part of the spindle, a tube provided on the side of barrel, an extruder sleeved on the tube, a connecting rod having one end pivotably connected to the extruder, a cam pivotably connected to the other end of the connecting rod, a motor, and a gear set for passing the motion of the motor to the cam.
The infrared sensor is activated when the transmitted ray is interrupted by an object (e.g., hand) which in turn causes motor to drive the feeding means. Then extruder is compressed to extrude soap through the outlet. Once a predetermined amount of soap is extruded the feeding means is deactivated by a dropping control mechanism (not further shown). Thus stops the extrusion of soap.
But this is unsatisfactory for the purpose for which the invention is concerned for the following reasons:
1. The setting of dropping is factory preset. For example, one drop or two drops. User is not allowed to set the device to drop more in each stretching out of one's hand. However, there are occasions such as in the hospital a large amount of soap required in each stretching out of one's hand. The only way to obtain such large amount of soap is to stretch out one's hand repeatedly until the required amount of soap is reached. This is quite inconvenient. PA1 2. The extruder may vibrate during the extrusion process. This causes a not so smooth operation of soap feeding device. Thus the feeding means needs to be improved.